Magnetic field reconnection in solar and stellar flares

Radio observations are sensitive to energetic electrons, and thus are an important tool for studying the properties of solar flares. High spatial resolution multifrequency observations at centimeter wavelengths can provide important information on the region of energy release during flares and, therefore, on their triggering mechanisms. The changes in polarization and its structure during the preflare and impulsive phase have led to inferences about magnetic field topology in the flaring region /1/. We have learnt that evolving magnetic field structures often trigger the flare /2/. In this paper, we discuss evidence for magnetic reconnection in both solar and stellar flares derived from radio observations. We present two cases of solar flares well-observed by the VLA which show interacting magnetic structures leading to a flare. Both cases are strongly suggestive of reconnection. In the second part of the paper we discuss more indirect evidence based on flares in the coronae of red dwarf stars.